Method, system, and program for storing data for retrieval and transfer

ABSTRACT

Provided is a method, system and program for storing data for later retrieval and for transfer within a storage hierarchy. A data storage subsystem stores both individual user files and also managed files, each managed file comprising an aggregation of multiple user files. After receiving user files from a client station, the subsystem stores user files in a retrieval storage pool to facilitate file retrieval. Criteria are subsequently applied to the user files stored in the retrieval storage pool to delete low or lower priority files from the retrieval storage pool. In addition, user files are aggregated in managed files for transfer to another location within the storage hierarchy.

BACKGROUND

1. Field

The present description relates to a method, system, and program forstoring data in a manner which facilitates data retrieval and transfer.

2. Description of Related Art

There are various known techniques for backing up data. These backuptechniques are often implemented using a storage-management server whichcan store data objects such as user files in one or more locations oftenreferred to as storage pools. The storage-management server frequentlyuses a database for tracking information about the stored objects,including the attributes and locations of the objects in the storagepools. 10031 One backup technique typically includes a “tape rotation”procedure, in which full, differential and incremental backups are madefrom a machine at a client node to a storage such as tape storage. Afull backup of all of the objects stored on a client node is usuallymade on a periodic basis (e.g., weekly). During each cycle from one fullbackup to the next full backup, differential backups may be made inwhich objects which have changed since the last full backup are backedup. Also incremental backups may be made in which objects which havechanged since the last backup operation are backed up. Thesedifferential or incremental backups are typically performed on a morefrequent basis than full backups. For example, differential orincremental backups may be performed daily. After some number of cyclesof full, differential and incremental backups, tapes from the earliestcycle are often reused.

In this approach, every object on the client machine is typically backedup every time a full backup is made, which can result in substantialnetwork traffic and demands for storage on the storage-managementserver. Another approach which is used by some storage-managementservers, such as the Tivoli Storage Manager™ (TSM™) product marketed byInternational Business Machines Corporation (IBM), utilizes a“progressive incremental” methodology, in which objects are backed uponce from a client node and thereafter are typically not backed up againunless the object changes. In combination with the progressiveincremental procedures, object-level policy rules may be used to controlthe retention time and the number of versions which are maintained forstored objects. For example, the storage-management server can beconfigured to retain an “active” version, that is, an object currentlyresiding on the client node, and a specified number of inactiveversions, that is, objects that once resided on the client node but havesince been deleted or modified.

Still further, a storage pool hierarchy may be implemented which allowsdata to be stored on a range of devices having varying characteristicssuch as cost and performance. Certain policies for managing data can beapplied at the storage pool level to determine the appropriate deviceupon which objects are to be stored.

After being stored on the storage-management server, data objects can bemoved and copied using data-transfer operations such as migration inwhich objects are moved from one storage pool to another storage pool.For example, an object may be migrated from relatively fast andexpensive storage such as a disk to relatively slow and inexpensivestorage such as tape. Additional data transfer operations includestorage pool backups in which objects in one storage pool are duplicatedor copied to another pool for availability and recovery purposes.

Various techniques have been applied or proposed to increase operationalefficiency. For example, storage pools for sequential-access media suchas magnetic tape can be configured for “collocation” which causes thestorage-management server to group data for the same client node on thesame tape or tapes. Also, small objects on the storage-management servercan be aggregated together into a single entity as they are received bythe storage-management server. U.S. Pat. No. 6,098,074 describes anaggregation technique in which objects being stored are aggregated intoa “managed file.” The objects may thereafter be tracked and moved as asingle managed file within the storage hierarchy. When appropriate,individual objects can be processed individually such as for deletion orretrieval operations.

Further improvements in data storage may be useful in a variety ofapplications.

SUMMARY OF ILLUSTRATED EMBODIMENTS

Provided is a method, system and program for storing data. A datastorage subsystem stores both individual user files and also managedfiles, each managed file comprising an aggregation of one or multipleuser files. Received user files from a client station are stored in aretrieval storage pool. Criteria are applied to user files stored in theretrieval storage pool to delete low or lower priority files from theretrieval storage pool. In addition, user files are aggregated inmanaged files.

In one embodiment, active files are designated high priority files andinactive files are designated low priority files. The active files maybe retained in the retrieval storage pool and the inactive files may bedeleted from the retrieval storage pool.

In another embodiment, criteria are applied to received user files tostore high priority files in the retrieval storage pool. Low priorityuser files are aggregated and stored in an aggregation storage pool.

In one embodiment, user files received from a first client station aredesignated high priority files for storage in the retrieval pool. Userfiles received from a second client station are designated low priorityfiles for aggregation and storage in an aggregation storage pool.

There are additional aspects to the present disclosure. It shouldtherefore be understood that the preceding is merely a brief summary ofsome embodiments and aspects of the present descriptions. Additionalembodiments and aspects are referenced below. It should further beunderstood that numerous changes to the disclosed embodiments can bemade without departing from the spirit or scope of this description. Thepreceding summary therefore is not meant to limit the scope of thisdescription.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers representcorresponding parts throughout:

FIG. 1 illustrates an example of a computing environment in whichaspects of the illustrated embodiments may be implemented;

FIG. 2 is a schematic diagram of a digital data processing machine ofthe embodiment of FIG. 1;

FIG. 3 shows an exemplary signal-bearing medium in accordance withdescribed embodiments;

FIG. 4 is a schematic diagram showing the subcomponents of anillustrative storage hierarchy in accordance with described embodiments;

FIG. 5 is a schematic diagram showing the interrelationship of variousillustrative user files and managed files;

FIG. 6 shows illustrative operations of an example of a data storagesubsystem in accordance with described embodiments;

FIGS. 7A-7D illustrate an example of file culling and aggregationoperations in accordance with described embodiments;

FIG. 8 illustrates a more detailed example of file culling andaggregation operations in accordance with described embodiments;

FIG. 9 shows an alternative example of operations of a data storagesubsystem in accordance with described embodiments;

FIG. 10 shows another alternative example of operations of a datastorage subsystem in accordance with described embodiments; and

FIG. 11 illustrates an architecture of computing components in a networkenvironment, such as the hosts, storage controllers, clusters, and anyother computing devices.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

In the following description, reference is made to the accompanyingdrawings which form a part hereof and which illustrate severalembodiments. It is understood that other embodiments may be utilized andstructural and operational changes may be made without departing fromthe scope of the present invention.

One aspect of the description provided herein concerns a storagemanagement system, which may be embodied by various hardware componentsand interconnections. One example is shown by the storage managementsystem 100 of FIG. 1. Broadly, the system 100 includes a data storagesubsystem 102, one or more administrator stations 104, and one or moreclient stations 106. The subsystem 102 operates in response todirections of the client stations 106, as well as the administratorstations 104.

The administrator stations 104 are used by system administrators toconfigure, monitor, and repair the subsystem 102. Under direction of anend user, the client stations 106 use the subsystem 102 to store andmanage data on their behalf. More particularly, each client station 106creates and regards data in the form of “user files”. In this regard,each client station 106 separately employs the subsystem 102 to archive,backup, retrieve, and restore its user files. Accordingly, each userfile is associated with a single client station 106, which is the sourceof that user file.

Each client station 106 may comprise any general purpose computer, suchas an RS-6000 based workstation, Intel-processor based personalcomputer, mainframe computer, etc. The client stations 106 may comprisesimilar or different machines, running the similar or differentoperating systems. Some exemplary operating systems include AIX™, UNIX,OS/2, WINDOWS™, etc.

The client stations 106 are interconnected to the subsystem 102 by anetwork 116. The network 116 may comprise any desired connection,including one or more conductive wires or busses, fiber optic lines,data communication channels, wireless links, internet connections,telephone lines, Storage Area Network (SAN), Local Area Network (LAN),Intranet, the Internet, Wide Area Network (WAN), etc. Preferably, a highspeed communication channel such as a T3 link is used, employing anetwork protocol such as TCP/IP.

The administrator stations 104 comprise electronic equipment for a humanor automated storage administrator to convey machine-readableinstructions to the subsystem 102. Thus, the stations 104 may compriseprocessor-equipped general purpose computers or “dumb” terminals,depending upon the specific application.

In an exemplary embodiment, the data storage subsystem 102 may comprisea commercially available server such as the Tivoli Storage Manager™(TSM™) product distributed by IBM, which has been modified to operate inaccordance with the description provided herein. However, since otherhardware arrangements may be used as well, a generalized view of thesubsystem 102 is discussed below.

The data storage subsystem 102 includes a data processing apparatus 108,having a construction as discussed in greater detail below. The dataprocessing apparatus 108 exchanges signals with the network 116 and theclient stations 106 via an interface 112, and likewise exchanges signalswith the administrator stations 104 via an interface 110. The interfaces110, 112 may comprise any suitable device for communicating with theimplemented embodiment of client station and administrator station. Forexample, the interfaces 110, 112 may comprise ETHERNET cards, smallcomputer system interfaces (“SCSIs”), parallel data ports, serial dataports, telephone modems, fiber optic links, wireless links, etc.

The data processing apparatus 108 is also coupled to a database 113 anda storage hierarchy 114. As discussed in greater detail below, thestorage hierarchy 114 is used to store selected individual user files ina nonaggregated collection. In addition, the storage hierarchy is usedto store “managed files”. Each managed file typically includes multipleconstituent user files stored together as an “aggregate” file. However,in some instances, a managed file may be an individual user file (storedas such). The subsystem's storage of user files in nonaggregated andaggregated form may protect these files from loss or corruption on theclient's machine, assist the clients by freeing storage space at theclient stations, and may also provide management of client data. In thisrespect, operations of the storage hierarchy 114 may include “archiving”files from the client stations 106, “backing up” files of the clientstations 106 to the storage hierarchy 114, “retrieving” stored files forthe client stations 106, and “restoring” files backed-up on thehierarchy 114. As will be explained in greater detail below, storingselected user files in non-aggregated form can facilitate datamanagement functions including restoration of backed up files whilestoring user files in aggregated form can promote efficient datatransfer within the hierarchy 114.

The database 113 contains information about the files contained in thestorage hierarchy 114. For example, as described in U.S. Pat. No.6,098,074, this information may include the addresses at which managedfiles are stored in the storage hierarchy 114, various characteristicsof the stored data, certain client-specified data managementpreferences, etc. The contents of the database 113 are discussed indetail below.

The data processing apparatus 108 may be embodied by various hardwarecomponents and interconnections. FIG. 2 shows one example, in the formof a digital data processing apparatus 200.

The apparatus 200 includes a processing unit 202, such as amicroprocessor or other processing machine, coupled to a storage unit204. In the present example, the storage unit 204 includes one or morestorage devices such as a fast-access storage 206 and a nonvolatilestorage 208. The fast-access storage 206 preferably comprises randomaccess memory, and may be used to store programming instructionsexecuted by the processing unit 202. The nonvolatile storage 208 maycomprise, for example, one or more magnetic data storage disks such as a“hard drive”, a tape drive, or any other suitable storage device. Theapparatus 200 also includes at least one input/output 210, such as aline, bus, cable, electromagnetic link, or other means for exchangingdata between the processing unit 202 and other components of thesubsystem 102.

Despite the specific foregoing description, ordinarily skilled artisans(having the benefit of this disclosure) will recognize that theapparatus discussed above may be implemented in a machine of differentconstruction, without departing from the scope of the invention. As aspecific example, one of the components 206 or 208 may be eliminated;furthermore, the storage unit 204 may be provided on-board theprocessing unit 202, or even provided externally to the apparatus 200.

The storage hierarchy 114 may be implemented in storage media of variousnumber and characteristics, depending upon the clients' particularrequirements. To specifically illustrate one example, FIG. 4 depicts arepresentative storage hierarchy 400. The hierarchy 400 includesmultiple levels 402-410, where successively higher levels representincrementally higher storage performance. The levels 402-410 providestorage devices with a variety of features and performancecharacteristics.

In this example, the first level 402 includes high-speed storagedevices, such as magnetic hard disk drives, writable optical disks, orother direct access storage devices (“DASDs”). The level 402 providesthe fastest data storage and retrieval time among the levels 402-410,albeit the most expensive. The second level 404 includes DASDs with lessdesirable performance characteristics than the level 402, but with lowerexpense. The third level 406 includes multiple optical disks and one ormore optical disk drives. The fourth and fifth levels 408-410 includeeven less expensive storage means, such as magnetic tape or anothersequential access storage device.

The levels 408-410 may be especially suitable for inexpensive, long-termdata archival, whereas the levels 402-406 are appropriate for short-termfast access data storage. As an example, one or more devices in thelevel 402 and/or level 404 may even be implemented to provide a datastorage cache.

Devices of the levels 402-410 may be co-located with the subsystem 102,or remotely located, depending upon the user's requirements. Thus,storage devices of the hierarchy 400 may be coupled to the dataprocessing apparatus 108 by a variety of means, such as one or moreconductive wires or busses, fiber optic lines, data communicationchannels, wireless links, internet connections, telephone lines, SCSIconnection, ESCON connect, etc.

Although not shown, the hierarchy 400 may be implemented with a singledevice type, and a corresponding single level. Ordinarily skilledartisans will-recognize the “hierarchy” being used illustratively, sincethe description provided herein includes but does not require ahierarchy of storage device performance.

In the context of the storage hierarchy 114/400, the term “storage pool”is used to identify one or more storage devices with similar performancecharacteristics. For instance, the level 404 may be comprised of severalstorage pools, each pool including one or more DASDs.

For further explanation of managed files, FIG. 5 shows an exemplary setof four managed files 502-504. Managed files are also referenced bycorresponding alphabetic designators A-B, for simpler representation invarious tables referenced below. For ease of explanation, upper casealphabetic designators refer to aggregate files, whereas lower casedesignators point out user files.

The managed file 502 includes multiple user files 502 a-502 p (alsoidentified by alphabetic designators a-p). The user files 502 a-502 pmay be stored contiguously, that is, adjacent to each other whenaggregated. In addition, the contiguous files may be stored withoutunused space between the adjacent files to conserve storage space.However, some empty storage space within a managed file may occur suchas when a constituent user file of the managed file is subsequentlydeleted.

The position of each user file in the managed file 502 is denoted by acorresponding one of the “offsets” 520. In an exemplary implementation,the offsets may represent bytes of data. Thus, the first user file 502 ahas an offset of zero bytes, and the second user file 502 b has anoffset of ten bytes. In the simplified example of FIG. 5, all user filesare ten bytes long. FIG. 5 also depicts managed file 504 which includesvarious user files. Managed files 502 and 504 include different sets ofuser files as shown in FIG. 5.

As previously mentioned, the database 113 is composed of variousinformation including tables that store information about data containedin the storage hierarchy 114. These tables include: an inventory table,a storage table, a mapping table, and a managed file attributes table.Each table provides a different type of information, exemplified in thedescription below. Ordinarily skilled artisans (having the benefit ofthis disclosure) will quickly recognize that the tables described beloware merely examples, that this data may be integrated, consolidated, orotherwise reconfigured, and that their structure and contents may besignificantly changed, all without departing from the scope of thepresent descriptions. For example, instead of tables, this data may beorganized as one or more object-oriented databases.

The information stored in the tables may be used in whole or in part,alone or in combination with other information, to identify whetherparticular user files are to be stored in either or both of retrievalstorage pools and aggregation storage pools as described above.Furthermore, the information stored in the tables may be used in wholeor in part, alone or in combination with other information, to identifywhether particular user files are to be culled from a retrieval storagepool and deleted.

In the illustrated embodiment, one table in the database 113 is aninventory table, an example of which is depicted in Table 1 of U.S. Pat.No. 6,098,074. The inventory table of this example contains informationspecific to each user file stored in the subsystem 102, regardless ofthe location and manner of storing the user files. Generally, theinventory table cross-references each user file with various “client”information and various “policy” information. More particularly, eachuser file is listed by its filename, which may comprise any alphabetic,alphanumeric, numeric, or other code uniquely associated with that userfile. The inventory table contains an entry for each user file.

The client information includes information relative to the clientstation 106 with which the user file is associated. In the illustratedexample, the client information is represented by “client number”,“client type”, and “source” fields in each record. For each user file,the “client number” field identifies the originating client station 106.This identification may include a numeric, alphabetic, alphanumeric, orother code. The “client type” field associates the client with one ormore predetermined categories, such as different computer types,operating systems, communications parameters, etc. The “source” fieldlists a location in the client station 106 where the user file is storedlocally by the client. As a specific example, a user file's source maycomprise a directory in the client station.

The policy information includes information concerning the client'spreferences for data management by the subsystem 102. Optimally, thisinformation includes the client's preferences themselves, as well asinformation needed to implement these preferences. In the illustratedexample, the policy information is represented by “data retention time”as well as other fields, listing a maximum number of backup versions tomaintain, timestamps of backed-up data, etc.

Another table in the database 113 is the storage table, an example ofwhich is depicted in Table 2 of U.S. Pat. No. 6,098,074. In contrast tothe inventory table (described above), the storage table containsinformation about where each managed file is stored in the storagehierarchy 114. The storage table contains an entry for each managedfile.

In the illustrated example, the storage table includes “managedfilename”, “storage pool”, “volume”, “location”, and other fields ineach record. The “managed filename” field lists the filename for eachmanaged file. Like the user files, each managed file has a filename thatcomprises a unique alphabetic, alphanumeric, numeric, or other code. Foreach managed file, the “storage pool” identifies a subset of the storagehierarchy 114 where the managed file resides. As mentioned above, each“storage pool” is a group of storage devices of the storage hierarchy114 having similar performance characteristics. For instance, each ofthe DASDs 402, DASDs 404, optical disks 406, tapes 408, and tapes 410may be divided into one or more storage pools. Identification of eachstorage pool may be made by numeric, alphabetic, alphanumeric, oranother unique code. In the illustrated example, numeric codes are used.

The “volume” field identifies a sub-part of the identified storage pool.In the data storage arts, data is commonly grouped, stored, and managedin “volumes”, where a volume may comprise a tape or a portion of a DASD.The “location” field identifies the corresponding managed file'slocation within the volume. As an example, this value may comprise atrack/sector combination (for DASDs or optical disks), a tachometerreading (for magnetic or optical tape), etc.

Another table in the database 113 is the mapping table, an example ofwhich is depicted in Table 3 of the U.S. Pat. No. 6,098,074. Generally,this table operates to bidirectionally cross-reference between managedfiles and user files. The mapping table identifies, for each managedfile, all constituent user files. Conversely, for each user file, themapping table identifies one or more managed files containing that userfile. In this respect, the specific implementation of Table 3 includes a“managed→user” field and a “user→managed” field.

The “managed→user” field contains multiple entries for each managedfile, each entry identifying one constituent user file of that managedfile. Each entry identifies a managed/user file pair by the managedfilename (“managed filename” field) and the user filename (“userfilename”).

Conversely, each entry of the “user→managed” field lists a single userfile by its name (“user filename” field), cross-referencing this userfile to one managed file containing the user file (“managed filename”).If the user file is present in additional managed files, the mappingtable contains another entry for each additional such managed file. Ineach entry, identifying one user/managed file pair, the record's userfile is also cross-referenced to the user file's length (“length” field)and its offset within the aggregated file of that pair (“offset” field).In this example, the length and offset are given in bytes.

The database 113 may also be implemented to include a number of othertables, if appropriate, the content and structure being apparent tothose of ordinary skill in the art (having the benefit of thisdisclosure). Some or all of these tables, for instance, may be added orincorporated into various existing tables discussed above. In oneembodiment, the database 113 includes a backup directory table thatindicates whether, for storage pool backup operations, each device ormedium in the storage hierarchy 114 is designated as a primary device,designated as a backup device, or has no designation yet.

FIG. 6 shows an example of operations of a data storage subsystem 102which stores both non-aggregated user files and aggregated user files tofacilitate data management operations and internal data transfers withinthe data storage hierarchy 114. Upon the receipt (block 620) of userfiles from one or more client stations 106, the user files may be stored(block 622) in nonaggregated form as individual user files in a storagepool 724 as schematically represented in FIG. 7A.

The storage pool 724 may be implemented with any type of storage device.However, in many applications, a storage device of a type similar to thefirst level 402 which includes high-speed storage devices, such asmagnetic hard disk drives which provide fast data storage and retrievaltime, may be appropriate for the storage pool 724. In one embodiment,the individual user files stored in the storage pool 724 may be used fora variety of data management functions including being retrieved torestore files on client stations 106 and other purposes. Thus, forconvenience, the storage pool 724 will be referred herein also as aretrieval storage pool 724.

FIG. 7A shows an example of three files, file 1, file 2, and file 3,from a client station 106, arriving (block 620 FIG. 6) at the datastorage subsystem 102 and being stored (block 622) in the retrievalstorage pool 724. Although three files are being shown being processed,it should be appreciated that the number of files received and processedmay number in the tens, hundreds or thousands, depending upon theparticular application.

In one embodiment, the user files may also be copied (block 626) toanother storage pool for backup purposes should the retrieval storagepool 724 fail or for other data management purposes. The backup copyingoperations may be performed serially or in parallel with otheroperations of the data storage subsystem 102 described herein.

In another aspect, the files stored in the retrieval storage pool 724may also be copied (block 630) for aggregation into a managed file. Themanaged file may subsequently be transferred in a data transferoperation such as a storage pool backup, a restore or reclamationoperation or a movement to another pool. Movement of a managed fileincludes migration to another location within the hierarchy 114. Thus,for example, FIG. 7B shows the files, file 1, file 2 and file 3aggregated as a managed file 732 and migrated to a tape drive 734 of thehierarchy 114. The subsystem 102 treats each managed file as a singlefile during migration, backup, and other subsystem operations, which canreduce the file management overhead to that of a single file.

In another aspect of the illustrated embodiments, criteria are applied(block 634, FIG. 6) to the individual user files stored in the retrievalstorage pool 724. In one embodiment, criteria are applied to distinguishindividual user files in groups of varying degrees of priority. The lowor lower priority user files may then be culled from the retrievalstorage pool 724 by “deleting” (block 636) those user files from theretrieval storage pool 724, leaving the high or higher priority userfiles in the retrieval storage pool 724.

For example, active user files could be designated (block 634) as highpriority files and inactive files could be designated as low priorityfiles. The low priority user files may then be deleted (block 636),leaving the active user files in the retrieval storage pool 724. In thismanner, space in the retrieval storage pool 724 may be conserved for thehigher priority files. In addition, for restore operations which utilizeactive files, such restore operations can be facilitated since theactive user files may be readily found in and retrieved from theretrieval storage pool 724, reducing or eliminating the need to accessmanaged files within the hierarchy 114. As explained below, a variety ofcriteria may be used to define groups of varying priority.

FIG. 7C shows an example of another three files, file 2 a, file 4, andfile 5 from a client station 106, arriving (block 620 FIG. 6) at thedata storage subsystem 102 and being stored (block 622) in the retrievalstorage pool 724. In this example, file 2 a is a modified version offile 2 previously received by the subsystem 102. Again, the user files,file 2 a, file 4, and file 5 may be copied (block 626) to anotherstorage pool for backup purposes should the retrieval storage pool 724fail or for other data management purposes. In one embodiment, retrievalpool files once copied to a backup storage pool can be marked as such inthe database 113 to avoid recopying for backup in a subsequent operationof block 626. Also, the files, file 2 a, file 4, and file 5, may becopied (block 630) and aggregated into a managed file. The managed filemay be transferred in a data transfer operation such as storage poolbackup, restore, reclamation or movement to another pool which includesmigration to another location within the hierarchy 114. Thus, forexample, FIG. 7D shows the files, file 2 a, file 4, and file 5aggregated as a managed file 752 and migrated to a tape drive 734 of thehierarchy 114 with the managed file 732. Again, in one embodiment,retrieval pool files once copied for aggregation may be marked as suchin the database 113 to avoid recopying for aggregation in a subsequentoperation of block 630.

Criteria are applied (block 634, FIG. 6) to the individual user filesstored in the retrieval storage pool 724. In this example, active userfiles are designated (block 634) as high priority files and inactivefiles are designated as low priority files. Also, in this example, file2 a is the latest or active version of file 2 such that file 2 becomesan “inactive” and therefore low priority file. Thus the low priorityuser files including file 2 may then be deleted (block 636) from theretrieval storage pool 724 as shown in FIG. 7D, leaving the active userfiles file 1, file 2 a, file 3, file 4, and file 5 in the retrievalstorage pool 724. Should a client station 106 need file 2 a to berestored to that station, file 2 a may readily found in and retrievedfrom the retrieval storage pool 724 without accessing managed fileswithin the hierarchy 114. Should an older version such as file 2 beneeded, it may be obtained from the managed file 732 which was migratedto another location.

The priority criteria of block 634 may be periodically applied (asindicated by a return arrow 638) to the files in the retrieval storagepool 724 to identify and cull low or lower priority files from theretrieval pool 724 since files may be downgraded from high to lowpriority upon expiration of predetermined periods of time.

FIG. 8 shows an example of the operations of block 630 in greaterdetail, in which user files are aggregated and migrated. Also, FIG. 8shows an example of the operations of blocks 634 and 636 in greaterdetail, in which lower priority user files are culled from the retrievalstorage pool 724. As previously mentioned in connection with FIG. 4, amigration operation can move managed files from higher levels (e.g. 402,404) to lower levels (e.g., 408, 410) in the storage hierarchy 400.Thus, migration movement may be “downward” relative to FIG. 4, therebymoving files from more expensive to less expensive storage devices. Insome cases, however, migration movement may be “upward” relative to FIG.4. This may occur, for example, in response to recent, frequent, oranticipated use of the files.

Once the migration is initiated (block 850), a determination (block 852)is made as to whether the appropriate “aggregate” has been opened forthe aggregation operation. As used herein, an aggregate is a collectionof individual user files being collected for combination into a singlemanaged file. As described in U.S. Pat. No. 6,098,074, various criteriamay be applied for this determination, depending upon the particularapplication. For example, the criteria may comprise a predeterminednumber of user files. For instance, a managed file may be created byincluding every ten user files being processed. In another example, thecriteria may specify a target managed file size; when enough user fileshave been processed to provide the desired size of managed file, themanaged file is completed.

The criteria may also consider other factors, for example groupingreceived user files according to their location within a client station106. As a further enhancement, the predetermined criteria may recognizecertain types of user files as being appropriate for being the sole userfile in a managed file. Moreover, ordinarily skilled artisans (havingthe benefit of this disclosure) will recognize many completely differentsuitable criteria suitable, without departing from the scope of thisdescription. Such criteria may further involve combinations and/orvariations of such different criteria as well as the criteria discussedabove.

If it is determined that an appropriate aggregate has not already beenopened, the appropriate aggregate is opened (block 854). The nextindividual user file is copied (block 856) to the open aggregate at anappropriate storage pool within the storage hierarchy 114. During thiscopy operation, the user file is read from the retrieval pool,aggregated and copied to the aggregation storage pool. However, theaggregation, including database table updating, can occur before, duringor after the copying operation.

A determination (block 860) is made as to whether the limit (such as themaximum size of the managed file or the number of user files to beaggregated in the open aggregate) has been reached. If not, adetermination (block 862) is made as to whether there are additionalfiles to be aggregated. If so, blocks 852-862 are repeated until themaximum has been reached (block 860) or there are no additional files tobe aggregated (block 862). Upon reaching (block 860) the limit, the openaggregate is closed (block 864) and a managed file has been created.

As a part of the aggregation process, in the illustrated embodiment, thesubsystem 102 enters a representation of the newly created managed fileand its relationship to its constituent user files in various tables ofthe database 113. An initial representation of the user files may bemade when those objects were first received and stored by the subsystem102. As described below, these representations involve entering: (1) theuser files in an inventory table (e.g., Table 1, described above, (2)the managed file in a storage table (e.g., Table 2, described above),(3) the managed file and its constituent user files in a mapping table(e.g., Table 3, described above), and (4) the managed file in a managedfile attributes table (e.g., Table 4, described above).

In the example of FIG. 8, the high priority user files are the activefiles and the low priority files are the inactive files. Accordingly,active/inactive criteria are applied (block 866) to the individual userfiles stored in the retrieval storage pool 724 to identify which userfiles are active and which are inactive. The inactive user files may bedeleted (block 868) from the source which, in this example, is theretrieval storage pool 724. As a result, the remaining user files in theretrieval storage pool 724 may be limited to active files. Thus, forrestore operations which utilize active files, such restore operationscan be facilitated since the active user files may be readily found inand retrieved from the retrieval storage pool 724 without accessingmanaged files within the hierarchy 114. However, for those restoreoperations which utilize user files to be found in the managed files,those user files may be retrieved in the manner described in U.S. Pat.No. 6,098,074.

A determination (block 870) is made as to whether there are anyadditional files to be copied for aggregation. If so, the operations ofblocks 852-870 are repeated until there are no additional files to copy(block 870) and the migration is ended (block 872). If it is determined(block 862) that there are no additional user files to copy before theaggregate limit has been reached (block 860), the aggregate may beclosed (block 864) ) and treated as a managed file. In the aggregationprocess, the subsystem 102 may enter a representation of the newlycreated managed file and its constituent user files in various tables ofthe database 113 as discussed above.

FIG. 9 shows an alternative example of operations of a data storagesubsystem 102 which stores both nonaggregated user files and aggregateduser files. In a manner similar to the operations of FIG. 6, upon thereceipt (block 910) of user files from one or more client stations 106,the user files may be stored (block 912) in nonaggregated form asindividual user files in a storage pool 724. In addition, the receivedindividual user files may be simultaneously aggregated (block 912) inone or more aggregation storage pools for aggregation into one or moremanaged files. In this manner, the received user files are initiallystored in a retrieval storage pool 724 and, in parallel, stored andaggregated in an aggregation storage pool. Again, criteria may beapplied to determine the appropriate aggregation pool for the receiveduser files to group the received user files as appropriate into variousmanaged files. The aggregation operation may be performed before, duringor after the transfer of the files to an aggregation pool.

In one embodiment, the user files may also be copied (block 914) fromthe retrieval storage pool 724 to another storage pool for backuppurposes should the retrieval storage pool 724 fail or for other datamanagement purposes. The backup copying operations may be performedserially or in parallel with other operations of the data storagesubsystem 102 described herein. In addition, criteria are applied (block916) to the individual user files stored in the retrieval storage pool724 to distinguish high priority individual user files from low priorityuser files. The low or lower priority user files may then be culled fromthe retrieval storage pool 724 by “deleting” (block 918) those userfiles from the retrieval storage pool 724, leaving the high or higherpriority user files.

FIG. 10 shows another alternative example of operations of a datastorage subsystem 102 which stores both nonaggregated user files andmanaged files, each managed file containing aggregated user files. Uponthe receipt (block 1030) of user files from one or more client stations106, criteria are applied (block 1032) to distinguish individual userfiles in groups of varying degrees of priority. The high or higherpriority user files may be stored (block 1034) in a retrieval storagepool 724 and the low or lower priority files may be aggregated in one ormore aggregation pools.

Again, various criteria may be applied to distinguish the received userfiles into groups of varying priority. For example, user files receivedfrom client stations 106 being used by key personnel could be designated(block 1032) as high priority and the user files received from the otherclient stations 106 could be designated as low priority user files. Thehigh priority user files received from the key personnel client stations106 could be stored (block 1034) in a retrieval storage pool 724. Thelow priority user files received from the other client stations 106could be stored in one or more aggregation pools for aggregation (block1034) in a manner similar to that discussed above. Hence, the lowpriority user files would not, in this example, be stored as individualuser files in a retrieval storage pool 724 but would be aggregated andstored as managed files. Again, the aggregation can occur before, duringor after the transfer of a user file to an aggregation storage pool.Other criteria may be used to determine which pool, retrieval oraggregation, a user file should be transferred, such as the type of fileincluding the age or version number.

In addition to the aggregation (block 1034) of the low or lower priorityuser files, the high or higher priority user files stored in theretrieval storage pool 724 may also be copied (block 1040) to anotherstorage pool for backup purposes should the retrieval storage pool 724fail or for other data management purposes. The backup copyingoperations may be performed serially or in parallel with otheroperations of the data storage subsystem 102 described herein.

In addition to the aggregation (block 1034) of the low or lower priorityuser files, the files stored in the retrieval storage pool 724 may alsobe copied (block 1042) for aggregation into a managed file. In addition,criteria may be applied (block 1044) to the individual user files storedin the retrieval storage pool 724 to distinguish individual user filesin groups of varying degrees of priority. One or more of the user filesinitially stored in the retrieval storage pool 724 because they wereinitially deemed to be high or higher priority files in a prior criteriaapplying operation (block 1032), may have subsequently become low orlower priority files because they have expired or have been supercededby a received later version. In which case, those user files which havebecome low or lower priority user files may then be culled from theretrieval storage pool 724 by “deleting” (block 1046) those user filesfrom the retrieval storage pool 724, leaving the high or higher priorityuser files in the retrieval storage pool 724.

The priority criteria applied to the received user files in theoperation of block 1032 may be the same or different from the prioritycriteria applied to the user files stored in the retrieval storage pool724 in the criteria applying operation of block 1044.

In the illustrated embodiment, the managed files created in theaggregation operations described above are available to participate ininternal data management operations, and to satisfy client requests.More particularly, the managed file (and the previously created managedfiles), may be used to satisfy client requests which may include manyoperations, such as user file delete, client retrieve, and clientrestore as described in U.S. Pat. No. 6,098,074.

Additional Implementation Details

The described techniques for managing resources may be implemented as amethod, apparatus or article of manufacture using standard programmingand/or engineering techniques to produce software, firmware, hardware,or any combination thereof. The term “article of manufacture” as usedherein refers to code or logic implemented in hardware logic (e.g., anintegrated circuit chip, Programmable Gate Array (PGA), ApplicationSpecific Integrated Circuit (ASIC), etc.) or a computer readable medium,such as magnetic storage medium (e.g., hard disk drives, floppy disks,tape, etc.), optical storage (CD-ROMs, optical disks, etc.), volatileand nonvolatile memory devices (e.g., EEPROMs, ROMs, PROMs, RAMs, DRAMs,SRAMs, firmware, programmable logic, etc.). Code in the computerreadable medium is accessed and executed by a processor complex. Thecode in which preferred embodiments are implemented may further beaccessible through a transmission media or from a file server over anetwork. In such cases, the article of manufacture in which the code isimplemented may comprise a transmission media, such as a networktransmission line, wireless transmission media, signals propagatingthrough space, radio waves, infrared signals, etc. Thus, the “article ofmanufacture” may comprise the medium in which the code is embodied.Additionally, the “article of manufacture” may comprise a combination ofhardware and software components in which the code is embodied,processed, and executed. Of course, those skilled in the art willrecognize that many modifications may be made to this configurationwithout departing from the scope of the present invention, and that thearticle of manufacture may comprise any information bearing medium knownin the art.

For example, in the context of FIGS. 1-2 the method aspect of thedescription provided herein may be implemented, by operating the dataprocessing apparatus 108 (embodied by a digital data processingapparatus 200), to execute a sequence of machine-readable instructions.These instructions may reside in various types of signal-bearing media.In this respect, one aspect of the present description concerns aprogrammed product, comprising signal-bearing media tangibly embodying aprogram of machine-readable instructions executable by a digital dataprocessor to perform a method of storing and using user files andmanaged files, each managed filed comprising an aggregation of one ormultiple individual user files.

Illustratively, this signal-bearing media may comprise RAM containedwithin the data processing apparatus 108, as represented by thefast-access storage 206 for example. Alternatively, the instructions maybe contained in another signal-bearing media, such as a magnetic datastorage diskette 300 (FIG. 3), directly or indirectly accessible by theprocessing unit 202. Whether contained in the digital data processingapparatus 200 or elsewhere, the instructions may be stored on a varietyof machine-readable data storage media, such as DASD storage (e.g., aconventional “hard drive” or a RAID array), magnetic tape, electronicread-only memory (e.g., ROM, EPROM, or EEPROM), an optical storagedevice (e.g. CD-ROM, WORM, DVD, digital optical tape), paper “punch”cards, or other suitable signal-bearing media including transmissionmedia such as digital and analog and communication links and wireless.In an illustrative embodiment of the invention, the machine-readableinstructions may comprise software object code, compiled from a languagesuch as C, C++, PLX, etc.

The illustrated logic of FIGS. 6, and 8-10 show certain events occurringin a certain order. In alternative implementations, certain operationsmay be performed in a different order, modified or removed. Moreover,operations may be added to the above described logic and still conformto the described implementations. Further, operations described hereinmay occur sequentially or certain operations may be processed inparallel. Yet further, operations may be performed by a singleprocessing unit or by distributed processing units.

FIG. 11 illustrates one implementation of a computer architecture 1100of the network components, such as the data storage subsystem 102,administrator stations 104 or client stations 106 shown in FIG. 1. Thearchitecture 1100 may include a processor 1102 (e.g., a microprocessor),a memory 1104 (e.g., a volatile memory device), and storage 1106 (e.g.,a nonvolatile storage, such as magnetic disk drives, optical diskdrives, a tape drive, etc.). The storage 1106 may comprise an internalstorage device or an attached or network accessible storage. Programs inthe storage 1106 are loaded into the memory 1104 and executed by theprocessor 1102 in a manner known in the art. The architecture furtherincludes a network card 1108 to enable communication with a network. Avideo controller 1109 controls a visual display. An input device 1110 isused to provide user input to the processor 1102, and may include akeyboard, mouse, pen-stylus, microphone, touch sensitive display screen,or any other activation or input mechanism known in the art. An outputdevice 1112 is capable of rendering information transmitted from theprocessor 1102, or other component, such as a display monitor, printer,storage, etc.

The foregoing description of various implementations of the presentdisclosure has been presented for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit the presentdescription to the precise form disclosed. Many modifications andvariations are possible in light of the above teaching. It is intendedthat the scope be limited not by this detailed description, but ratherby the claims appended hereto.

1. A data management method, comprising: receiving multiple user filesfrom at least one client station coupled to a data storage subsystem;storing at least some of the multiple user files in a retrieval storagepool at a first location in the data storage subsystem; creating amanaged file comprising an aggregation of at least some of the multipleuser files; applying first predetermined criteria to a user file storedin the retrieval storage pool to designate the user file in theretrieval storage pool as one of a higher priority and a lower priority;and deleting from said retrieval storage pool a user file designated aslower priority.
 2. The method of claim 1 further comprising retaining insaid retrieval storage pool a user file designated as higher priority.3. The method of claim 1 wherein said first predetermined criteriainclude the status of the user file as one of active and inactivewherein an active user file currently resides on said client station andis designated a higher priority user file, and an inactive user fileonce resided on a client station but has been subsequently at least oneof modified and deleted on said client station, and is designated alower priority user file.
 4. The method of claim 1 wherein saidretrieval storage pool is located in a disk storage.
 5. The method ofclaim 1 wherein said managed file creating includes copying user filesto an aggregation storage pool and designating the aggregation of userfiles in the aggregation storage pool as a single file in a database. 6.The method of claim 5 further comprising transferring said managed filefrom said aggregation storage pool to another location within a datahierarchy in the data storage subsystem.
 7. The method of claim 5wherein said copying includes copying user files from the retrievalstorage pool to the aggregation storage pool.
 8. The method of claim 5wherein said aggregation storage pool is located in a tape storage. 9.The method of claim 6 wherein said managed file is migrated to a tapestorage.
 10. The method of claim 1 further comprising copying receiveduser files to an aggregation storage pool wherein said managed filecreating includes creating a managed file comprising a contiguousaggregation of said user files copied to said aggregation storage pool.11. The method of claim 10 further comprising applying secondpredetermined criteria to a user file received from a client station todesignate the received user file as one of a higher priority and a lowerpriority, and wherein said retrieval storage pool storing includesstoring received user files designated as higher priority in saidretrieval storage pool, and wherein said copying to an aggregationstorage pool includes copying received user files designated as lowerpriority to said aggregation storage pool.
 12. The method of claim 11wherein each client station has an identity and said secondpredetermined criteria include the identity of the client station whichwas the source of a received user file wherein a user file received froma first client station is designated a higher priority user file and isstored in said retrieval storage pool, and a user file received from asecond client station is designated a lower priority user file and isstored in said aggregation storage pool.
 13. The method of claim 12wherein said first predetermined criteria include the status of the userfile as one of active and inactive wherein an active user file currentlyresides on said client station and is designated a higher priority userfile, and an inactive user file once resided on a client station but hasbeen subsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 14. An article ofmanufacture for managing data, wherein the article of manufacture causesoperations to be performed, the operations comprising: receivingmultiple user files from at least one client station coupled to a datastorage subsystem; storing at least some of the multiple user files in aretrieval storage pool at a first location in the data storagesubsystem; creating a managed file comprising an aggregation of at leastsome of the multiple user files; applying first predetermined criteriato a user file stored in the retrieval storage pool to designate theuser file in the retrieval storage pool as one of a higher priority anda lower priority; and deleting from said retrieval storage pool a userfile designated as lower priority.
 15. The article of claim 14 furthercomprising the operation of retaining in said retrieval storage pool auser file designated as higher priority.
 16. The article of claim 14wherein said first predetermined criteria include the status of the userfile as one of active and inactive wherein an active user file currentlyresides on said client station and is designated a higher priority userfile, and an inactive user file once resided on a client station but hasbeen subsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 17. The articleof claim 14 wherein said retrieval storage pool is located in a diskstorage.
 18. The article of claim 14 wherein said managed file creatingincludes copying user files to an aggregation storage pool anddesignating the aggregation of user files in the aggregation storagepool as a single file in a database.
 19. The article of claim 18 furthercomprising the operation of transferring said managed file from saidaggregation storage pool to another location within a data hierarchy inthe data storage subsystem.
 20. The article of claim 18 wherein saidcopying includes copying user files from the retrieval storage pool tothe aggregation storage pool.
 21. The article of claim 18 wherein saidaggregation storage pool is located in a tape storage.
 22. The articleof claim 19 wherein said managed file is migrated to a tape storage. 23.The article of claim 14 further comprising the operation of copyingreceived user files to an aggregation storage pool wherein said managedfile creating includes creating a managed file comprising a contiguousaggregation of said user files copied to said aggregation storage pool.24. The article of claim 23 further comprising the operation of applyingsecond predetermined criteria to a user file received from a clientstation to designate the received user file as one of a higher priorityand a lower priority, and wherein said retrieval storage pool storingincludes storing received user files designated as higher priority insaid retrieval storage pool, and wherein said copying to an aggregationstorage pool includes copying received user files designated as lowerpriority to said aggregation storage pool.
 25. The article of claim 24wherein each client station has an identity and said secondpredetermined criteria include the identity of the client station whichwas the source of a received user file wherein a user file received froma first client station is designated a higher priority user file and isstored in said retrieval storage pool, and a user file received from asecond client station is designated a lower priority user file and isstored in said aggregation storage pool.
 26. The article of claim 25wherein said first predetermined criteria include the status of the userfile as one of active and inactive wherein an active user file currentlyresides on said client station and is designated a higher priority userfile, and an inactive user file once resided on a client station but hasbeen subsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 27. A subsystemfor managing data for use with a plurality of client stations, eachclient station having user files, comprising: a plurality of datastorage devices wherein at least one data storage device has a retrievalpool adapted to store user files; a digital data processing apparatuscoupled to the storage devices, wherein the digital data processingapparatus is programmed to perform a data management method, said methodcomprising: receiving multiple user files from at least one clientstation coupled to the subsystem; storing at least some of the multipleuser files in said retrieval storage pool; creating a managed filecomprising an aggregation of at least some of the multiple user files;applying first predetermined criteria to a user file stored in theretrieval storage pool to designate the user file in the retrievalstorage pool as one of a higher priority and a lower priority; anddeleting from said retrieval storage pool a user file designated aslower priority.
 28. The subsystem of claim 27 wherein the method furthercomprises retaining in said retrieval storage pool a user filedesignated as higher priority.
 29. The subsystem of claim 27 whereinsaid first predetermined criteria include the status of the user file asone of active and inactive wherein an active user file currently resideson said client station and is designated a higher priority user file,and an inactive user file once resided on a client station but has beensubsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 30. The subsystemof claim 27 wherein said data storage devices include a disk storage andwherein said retrieval storage pool is located in said disk storage. 31.The subsystem of claim 27 further comprising a database and wherein atleast one data storage device has an aggregation storage pool andwherein said managed file creating includes copying user files to saidaggregation storage pool and designating the aggregation of user filesin the aggregation storage pool as a single file in said database. 32.The subsystem of claim 31 wherein a plurality of said data storagedevices are arranged in a data hierarchy and wherein the method furthercomprises transferring said managed file from said aggregation storagepool to another location within said data hierarchy.
 33. The subsystemof claim 31 wherein said copying includes copying user files from theretrieval storage pool to the aggregation storage pool.
 34. Thesubsystem of claim 31 wherein said data storage devices include a tapestorage and wherein said aggregation storage pool is located in saidtape storage.
 35. The subsystem of claim 32 wherein said data storagedevices include a tape storage and wherein said managed file is migratedto said tape storage.
 36. The subsystem of claim 27 further comprising adatabase and wherein at least one data storage device has an aggregationstorage pool and wherein the method further comprises copying receiveduser files to said aggregation storage pool wherein said managed filecreating includes creating a managed file comprising a contiguousaggregation of said user files copied to said aggregation storage pool.37. The subsystem of claim 36 further comprising the operation ofapplying second predetermined criteria to a user file received from aclient station to designate the received user file as one of a higherpriority and a lower priority, and wherein said retrieval storage poolstoring includes storing received user files designated as higherpriority in said retrieval storage pool, and wherein said copying to anaggregation storage pool includes copying received user files designatedas lower priority to said aggregation storage pool.
 38. The subsystem ofclaim 37 wherein each client station has an identity and said secondpredetermined criteria include the identity of the client station whichwas the source of a received user file wherein a user file received froma first client station is designated a higher priority user file and isstored in said retrieval storage pool, and a user file received from asecond client station is designated a lower priority user file and isstored in said aggregation storage pool.
 39. The subsystem of claim 38wherein said first predetermined criteria include the status of the userfile as one of active and inactive wherein an active user file currentlyresides on said client station and is designated a higher priority userfile, and an inactive user file once resided on a client station but hasbeen subsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 40. A server formanaging data for use with at least one data storage device and with aplurality of client stations, each client station-having user files,comprising: data processing means for managing data, said dataprocessing means having means for: creating a retrieval storage pool ina data storage device; receiving multiple user files from at least oneclient station coupled to the server; storing at least some of themultiple user files in said retrieval storage pool; creating a managedfile comprising a contiguous aggregation of at least some of themultiple user files; applying first predetermined criteria to a userfile stored in the retrieval storage pool to designate the user file inthe retrieval storage pool as one of a higher priority and a lowerpriority; and deleting from said retrieval storage pool a user filedesignated as lower priority.
 41. The server of claim 40 wherein thedata processing means further has means for retaining in said retrievalstorage pool a user file designated as higher priority.
 42. The serverof claim 40 wherein said first predetermined criteria include the statusof the user file as one of active and inactive wherein an active userfile currently resides on said client station and is designated a higherpriority user file, and an inactive user file once resided on a clientstation but has been subsequently at least one of modified and deletedon said client station, and is designated a lower priority user file.43. The server of claim 40 wherein said data storage devices include adisk storage and wherein said retrieval storage pool is located in saiddisk storage.
 44. The server of claim 40 wherein said data processingmeans further has a database and wherein at least one data storagedevice has an aggregation storage pool and wherein said managed filecreating includes copying user files to said aggregation storage pooland designating the aggregation of user files in the aggregation storagepool as a single file in said database.
 45. The server of claim 44wherein a plurality of said data storage devices are arranged in a datahierarchy and wherein the data processing means further has means fortransferring said managed file from said aggregation storage pool toanother location within said data hierarchy.
 46. The server of claim 40wherein said data processing means further has a database and wherein atleast one data storage device has an aggregation storage pool andwherein the data processing means further has means for copying receiveduser files to said aggregation storage pool wherein said managed filecreating includes creating a managed file comprising a contiguousaggregation of said user files copied to said aggregation storage pool.47. The server of claim 46 wherein the data processing means further hasmeans for applying second predetermined criteria to a user file receivedfrom a client station to designate the received user file as one of ahigher priority and a lower priority, and wherein said retrieval storagepool storing includes storing received user files designated as higherpriority in said retrieval storage pool, and wherein said copying to anaggregation storage pool includes copying received user files designatedas lower priority to said aggregation storage pool.
 48. The server ofclaim 47 wherein each client station has an identity and said secondpredetermined criteria include the identity of the client station whichwas the source of a received user file wherein a user file received froma first client station is designated a higher priority user file and isstored in said retrieval storage pool, and a user file received from asecond client station is designated a lower priority user file and isstored in said aggregation storage pool.
 49. The server of claim 48wherein said first predetermined criteria include the status of the userfile as one of active and inactive wherein an active user file currentlyresides on said client station and is designated a higher priority userfile, and an inactive user file once resided on a client station but hasbeen subsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 50. A datamanagement method, comprising: receiving multiple user files from atleast one client station coupled to a data storage subsystem; storing atleast some of the multiple user files in a retrieval storage pool at afirst location in the data storage subsystem; creating a managed filecomprising an aggregation of at least some of the multiple user files,wherein said managed file creating includes copying user files to anaggregation storage pool and designating the aggregation of user filesin the aggregation storage pool as a single file in a database.;applying first predetermined criteria to a user file stored in theretrieval storage pool to designate the user file in the retrievalstorage pool as one of a higher priority and a lower priority; deletingfrom said retrieval storage pool a user file designated as lowerpriority; and retaining in said retrieval storage pool a user filedesignated as higher priority.
 51. The method of claim 50 wherein saidfirst predetermined criteria include the status of the user file as oneof active and inactive wherein an active user file currently resides onsaid client station and is designated a higher priority user file, andan inactive user file once resided on a client station but has beensubsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file.
 52. The method ofclaim 50 further comprising applying second predetermined criteria to auser file received from a client station to designate the received userfile as one of a higher priority and a lower priority, and wherein saidretrieval storage pool storing includes storing received user filesdesignated as higher priority in said retrieval storage pool, andwherein said copying to an aggregation storage pool includes copyingreceived user files designated as lower priority to said aggregationstorage pool.
 53. A data management method, comprising: receivingmultiple user files from at least one client station coupled to a datastorage subsystem; applying first predetermined criteria to a user filereceived from a client station to designate the received user file asone of a higher priority and a lower priority; storing user filesdesignated a higher priority in a retrieval storage pool in a diskstorage in the data storage subsystem; creating a managed filecomprising a contiguous aggregation of multiple user files eachdesignated lower priority, wherein said managed file creating includescopying lower priority user files to an aggregation storage pool in atape drive and designating the aggregation of user files in theaggregation storage pool as a single file in a database; applying secondpredetermined criteria to a user file stored in the retrieval storagepool to designate the user file in the retrieval storage pool as one ofactive and inactive wherein an active user file currently resides onsaid client station and is designated a higher priority user file, andan inactive user file once resided on a client station but has beensubsequently at least one of modified and deleted on said clientstation, and is designated a lower priority user file; deleting fromsaid retrieval storage pool a user file designated as inactive; andretaining in said retrieval storage pool a user file designated asactive.
 54. The method of claim 53 wherein each client station has anidentity and said first predetermined criteria include the identity ofthe client station which was the source of a received user file whereina user file received from a first client station is designated a higherpriority user file and is stored in said retrieval storage pool, and auser file received from a second client station is designated a lowerpriority user file and is stored in said aggregation storage pool.